Additive manufacturing or 3D printing is a process of making a 3D solid object of virtually any shape from a digital model. 3D printing is achieved using an additive process, where successive layers of material are laid down in different shapes. 3D printing is also considered distinct from traditional machining techniques, which mostly rely on the removal of material by methods such as cutting or drilling (subtractive processes).
A materials printer usually performs 3D printing processes using digital technology. The first working 3D printer was created in 1984 by Chuck Hull of 3D Systems Corp. Since the start of the 21st century there has been a large growth in the sales of these machines, and their price has dropped substantially.
The 3D printing technology is used for both prototyping and distributing manufacturing with applications in architecture, construction (AEC), industrial design, automotive, aerospace, military, engineering, civil engineering, dental and medical industries, biotech (human tissue replacement), fashion, footwear, jewelry, eyewear, education, geographic information systems, food, and many other fields. It has been speculated that 3D printing may become a mass market item because open source 3D printers can easily offset their capital costs by enabling consumers to avoid costs associated with purchasing common household objects.
Bioengineers take a 3-D scan of a child’s ear, design a seven-part mold in the SolidWorks CAD program, and print the pieces. The mold is injected with a high-density gel made from 250 million bovine cartilage cells and collagen from rat tails (the latter serves as a scaffold). After 15 minutes, the ear is removed and incubated in cell culture for several days. In three months, the cartilage will have propagated enough to replace the collagen.
A 3-D bioprinter deposits multiple types of kidney cells—cultivated from cells taken by a biopsy—while simultaneously building a scaffold out of biodegradable material. The finished product is then incubated. The scaffold, once transplanted into a patient, would slowly biodegrade as the functional tissue grows.
Using an open-source RepRap printer and custom software, researchers print a network of sugar filaments inside a mold and coat the filaments in a polymer derived from corn. They then dispense a gel containing tissue cells into the mold. Once it sets, they wash the structure in water, which dissolves the sugar and leaves empty channels in the tissue.
A custom bioprinter scans and maps the patient’s wound. One inkjet valve ejects the enzyme thrombin, and another ejects cells mixed with collagen and fibrinogen (thrombin and fibrinogen react to create the blood coagulant fibrin). Then, the printer deposits a layer of human fibroblasts, followed by a layer of skin cells called keratinocytes.
Researchers print scaffolds with a ceramic powder (human bone is 70 percent ceramic), using the same 3-D printers that produce metal parts found in electric motors. An inkjet covers the ceramic with a layer of plastic binder. This structure is baked at 2,282˚F for 120 minutes and placed into a culture with human bone cells. After a day, the scaffold supports them.
Source: http://www.popsci.com/science/ (Popular Science Magazine)